Rope-knotting/tying for Linear Puncher

Hey there guys,

We have a pretty effective LP that shoots at ~2 balls per second, long range and mid range. We use the slip-gear mechanism to wind up and then release the launcher, and for our stopper we have some rope that we have threaded through a c channel. The rope works great throughout the duration of a match and has never gotten cut/broken, but every few matches we find ourselves needing to add an additional knot (the ‘simple’ kind, IDK what you call them) in order to keep the launching distance the same.

Obviously, this isn’t optimal and can also lead to a little variation between the shots. While we are working on keeping an accuracy of around 90-95%, it’s the little things like this that start adding up to missing 2-3 balls. I was wondering what some better knots/mechanisms to tie rope were, since ideally we would like the rope to either always stay taut, or to be easily made a little tighter without having to add an entire new knot.

Thanks for any help you guys can provide!

If you want a knot that lets you adjust the tension on it easily, you might take a look at a taut line hitch (Google Video search for taut line hitch). I’m not sure if the force of the puncher is enough to cause the knot to slip, but I don’t think it is. It’s a really simple knot to tie, and it lets you slide the knot up and down to increase or decrease tension. It basically forms a loop and makes the loop bigger or smaller. As the loop gets bigger, the tension increases.

My advice would be to not use string. I have experimented a lot with it and it always will stretch out over time. I have come up with a non string stop that works just fine and stops the puncher in the same place every time. String is by no means the only possible stop and in my experience is problematic.

Do you mind sharing the mechanism?

You will probably be able to see it either in upcoming skill runs videos or our state reveal. But its honestly not that complicated.

I thought you were dominating with your single flywheel? You’re certainly amongst the top team signed up for states.

As Grant said, the string is going to stretch with use so it will not remain taut. If you are sticking with the string, lpieroni’s suggestion of the taut line hitch is a good one. You could also consider the sheep shank. If you are using the over hand knot now, and finding you it’s getting pulled too tight and you can’t get it undone to retie it, the figure 8 knot or some of the other stopper knots would be a better choice.

taughtline hitch will slip underthose types of loads, use half hitches instead. these are usualy used in groups of two called, snsuprisingly “two half hitches” how ever you can keep adding them to have 3 or 4 half hitches and more strength